Correct. You successfully identified and labeled polynomials in the form $\displaystyle{{a}}^{{2}}+{2}{a}{b}+{{b}}^{{2}}\usepackage{cmbright}\Huge\$ , $\displaystyle{{a}}^{{2}}-{2}{a}{b}+{{b}}^{{2}}\usepackage{cmbright}\Huge\$ , and $\displaystyle{{a}}^{{2}}-{{b}}^{{2}}\usepackage{cmbright}\Huge\$ . Notice that the square of a sum has no subtraction signs in it, whereas a square of a difference has one multiplication sign. The product of a sum and a difference has only two terms.